Apparatus for producing elasticized thermoplastic yarns



Jan. 19, 1960 F. w. cox ET AL APPARATUS FOR PRODUCING ELASTICIZEDTHERMOPLASTIC YARNS 5 Sheets-Sheet 1 Filed Jan. 26, 1956 IN VEN TORSFRED W. COX CYRIL G. EVANS ATTORNEY Jan. 19, 1960' F. w. cox ET ALAPPARATUS FOR PRODUCING ELASTICIZED THERMOPLASTIC YARNS 3 Sheets-Sheet 2Filed Jan. 26, 1956 FIG-6- INVEN TORS FRED W. OOX BY CYRIL G. EVANS M amATTORNEY Jan. 19, 1960 F. w. cox ETAL 2,921,358

APPARATUS FOR PRODUCING ELASTICIZED THERMOPLASTIC YARNS Filed Jan. 26,1956 3 Sheets-Sheet 3 INVENTORS FRED W. COX CYRIL. G. EVANS WMMMATTORNEY APPARATUS FOR PRQBUCKNG ELASTICIZED THERMlJfLASTitC YARNS FredW. Cox, Pendieton, and (Zyril G. Evans, Clemson,

S.C., 'assignors to Deering Milliken Research Corporation, Pendleton,5.0., a corporation of Delaware Application .lanuary 26, 1956, SerialNo. 561,563

24 Qlaims. (Cl. 28-1) This invention relates to improved methods andapparatus for the manufacture of crinkled or coiled yarns having anelastic nature and, more particularly, the invention relates to theelasticization of yarns by passing the same through a sharply angularpath under tension.

Apparatus for producing elasticized yarn by passing a thermoplasticstrand under tension through an angular path is now well known in theart and constitutes a part of the subject matter of copendingapplication, Serial Number 274,358, filed March 1, 1952. The type ofapparatus most commonly employed for producing elasticized yarn by thisprocedure comprises a flattened heater strip or plate, against which theyarn is drawn in sliding frictional contact, and a blademembefpositioned with its edge in close proximity to the heater plate orstrip so that the yarn can be drawn around the blade edge after beingheated by its contact with the stationary heating means. While suchapparatus is capable of producing an excellently elasticized yarn, theapparatus nevertheless leaves room for improvement in several respects.

A first disadvantage of the prior art apparatus is that it requiressliding frictional contact of the yarn with the surface of a yarn heaterand this may result, in some instances, in objectionable abrasion of theyarn.

Still another disadvantage of the prior art apparatus is that in someinstances the yarn cannot be supplied to the blade edge under a lowenough tension to result in the highest degree of elasticization. Inorder for the yarn to be heated satisfactorily, it is necessary that itbe in firm contact with the plate, and in some instances if one obtainssufficient contact with the plate to result in the yarn being adequatelyheated, the tension necessary to draw the yarn over the plate is inexcess of that at which it is most advantageously drawn about the bladeedge. This is particularly true if one attempts to utilize high linearyarn velocities since high velocities require a correspondingly greaterlength of contact with the heater plate or strip in order for thetemperature of the yarn to be uniformly raised to a proper value forelasticization.

Still another disadvantage of the prior art apparatus is that itprovides inadequate tension regulation in some instances and inparticular when yarns of very low deniers are being processed. Thedifliculties of supplying a yarn end under a very low but constanttension will be ap parent to those skilled in the art and yet anyvariation in tension in the yarn being passed about the blade edgeresults in large differences in the degree of elasticization obtained. Anon-uniformly elasticized yarn is not only objectionable because of itslower average degree of elasticity, but because it also tends to resultin woven or knitted goods having a non-uniform appearance.

It is a primary object of this invention to provide yarn elasticizingapparatus which overcomes the above described disadvantages.

It is another object of the invention to provide apparatus which canconstitute a component part of the Patented Jan. 19, 1960 equipmentconventionally required in the production of thermoplastic yarns.

These as well as other objects of the invention are accomplished byapparatus comprising a roll having a yarn engaging peripheral surface,and means to position a blade means providing a yarn engaging edgeadjacent the periphery of said roll such that an end of yarn passingbetween the periphery of the roll and said edge can be withdrawn fromthe surface of the roll about said edge in an angular path with saidedge positioned at the apex of the angle. To heat the yarn so that itpasses about the yarn engaging edge of the blade means at an elevatedtemperature, it is only necessary to heat at least a portion of theperipheral surface of the roll. The roll can conveniently constitute oneelement of a yarn storage device which in turn may constitute a part ofthe yarn production equipment now employed in the manufacture ofthermoplastic yarns. For example, certain types of draw twisters mayreadily be modified according to this invention to thereby permitincorporation of yarn elasticization into the drawn twisting operation.

In View of the above, it will be appreciated that in apparatus accordingto this invention, the yarn need be in sliding frictional contact onlywith the edge of the blade means and further that the tension in theyarn passing about the blade edge may be as low as is desired. In otherWords, the surface of the roll which heats the yarn also serves toadvance the yarn at a reasonably constant rate so that the tension inthe yarn as it passes about the blade edge can be regulated entirely bythe yarn collecting or advancing means which withdraws the yarn from theblade edge.

Several specific embodiments of the invention will now be described withreference to the accompanying drawings in which:

Figure l is a front plan View of one form of apparatus according to thisinvention,

Figure 2 is an end view of a portion of the apparatus of Figure 1,

Figure 3 is a cross sectional view taken substantially along the line3-3 in Figure 2,

Figure 4 is an enlarged view of the blade holding means utilized in theapparatus of Fiagure 1,

Figure 5 is a cross sectional view taken along the line 5-5 of Figure 4of the drawings,

Figure 6 is a front plan view of a second form of apparatus according tothe invention,

Figure 7 is a cross-sectional view taken along the line 7-7 of Figure 6,

Figure 8 is a front plan View of still another form of apparatusaccording to the invention,

Figure 9 is a cross sectional view of a portion of the apparatus ofFigure 8 taken substantially along the line With reference to Figures 1to 5 of the drawings, the reference numeral ll? indicates a conventionalsupply means for furnishing an end of yarn 11. The yarn supply means ishere illustrated as comprising a bobbin, cop or the like but may be'anyother suitable means for supplying a continuous filament yarn. Forexample, if the apparatus of this invention is to be constructed bymodification of a draw twister, the yarn can be supplied directly from ahardening bath or drying chamber into which it is introduced from aspinnerette or the like.

The reference numeral 12 indicates a support member, which can be a partof a draw twister or spinning frame, and extending from the supportmember 12 is a stub shaft 14. The stub shaft 14 may be secured to thesupport member 12 in any suitable manner as for example by means of anut 16. The reference numeral 18 generally indicates a roll member whichis journaled for rotation on shaft 14 by means of anti-friction bear-rings 20 and 22 and which is provided with a plurality of gear teeth 24extending about the periphery of an end member 26. Means are providedfor driving the roll 18 comprising a small gear 28 which meshes with theteeth 24 and which is carried by a driven shaft 30 illustrated as beingjournaled through the frame member 12.

The roll member 18 embodies two yarn engaging drum portions 32 and 34 ofdifferent diameters. The larger drum portion 32, which may be formed ofany suitable heat conducting material such as stainless steel, isprovided with an annular flange 36 and is secured to end member 26 byany suitable means such as by screws 38. The smaller drum portion 34 isprovided with an inwardly extending annular flange 40 which is securedto drum portion 32 by any suitable means such as screws 42. Preferably,for reasons which will subsequently become apparent, the portion 34 isthermally insulated'from portion 32, for example by means of a thinannular gasket 43 formed of a material having a low heat conductivitysuch as cork, or, if desired, the entire drum portion 34 may be formedof a material having a low coefficient of thermal conductivity.

Positioned within drum section 32 in close proximity to the innersurface thereof is an annular heater 44. The heater 44 is illustrated asbeing of the electrical resistance type and is designed to retain aportion of the yarn engaging surface of drum portion 32 at an elevatedtemperature. The heater is illustrated as being supported from stubshaft 14 by a series of support members 46 and is supplied withelectrical power by means of electrical conductors 48 extending throughan axial passage in stub shaft 14. A thermostat 50 is preferablyprovided for temperature regulation.

Journaled about a stub shaft 52 extending from frame member 12 is asecond roll member generally indicated by the reference numeral 54. Rollmember 54 is also provided with a first portion 56 and a second portion58 of different diameters such that when the peripheral speed of portion56 is equal to the peripheral speed of drum portion 32 of roll 18, theperipheral speed of section 58 of roll 54 will be equal to theperipheral speed of drum portion 34 of roll 18. Roll 54 is rotatableabout an axis which is at an angle to the axis of rotation of roll 18 sothat when yarn end 11 is wrapped a plurality of turns about the tworolls, adjacent wraps of yarn remain separated from each other asillustrated in the drawings, and it will be apparent that rolls 18 and54 together constitute a yarn storage device of a conventional type.

Extending from member 12 is a support arm 60 which constitutes a part ofa blade holding means to secure a blade member 62, having a yarnengaging edge 64, in operative position with the edge 64 positionedcontiguous to the heated peripheral surface of the drum portion 32 ofroll 18. The blade member 62 is illustrated as being seated in asuitable indentation in a plate member 66 carried by arm 60 and since itis generally advantageous that the blade 62 be retained at a lowtemperature relative to the drum portion 32 of roll 18, both platemember 66 and arm 60 are preferably formed of a material having a highspecific thermal conductivity, such as bronze, so that heat is rapidlyremoved from the blade member. The blade member 62 is preferably mountedin such a manner that it is readily removable and is illustrated asbeing secured in position by a pair of clip members 68 attached to platemember 66 by any suitable means such as by screws 70.

The reference numeral 72 generally indicates a yarn takeup device hereillustrated as comprising a conventional ring and traveler array. Anapex guideor the like 74 guides the yarn end 11 into a yarn balloon fromwhich it passes under a rotating traveler 76 and is wound upon asuitable bobbin 78. It will be understood that the takeup means may beof any conventional type and that in some instances it may be desirableto employ a takeup means of a type which does not result in the yarnbeing twisted.

In order to define a proper yarn path for yarn end 11, the apparatus isprovided with several yarn guide means. A first guide means 80 isillustrated as being positioned immediately above the yarn supply 10 andpermits the yarn end 11 to be withdrawn from the supply package in anover-end manner. A guide 82 and a guide 84 lead the yarn to a properposition on roll 18 and a guide 86 insures that the yarn is withdrawnfrom the roll 18 at a proper angle with respect to the axis of rotationof the roll. The yarn path between the guides 82 and 84 and between theguides 86 and 74 is illustrated as being discontinuous since, in manyinstances, it may be advantageous to conduct operations between thesepoints that are not directly related to yarn elasticization. Forexample, it may be desirable to pass the yarn around a yarn storagedevice and a snubbing pin between the guides 82 and 84 so that the yarnis permanently elongated in a conventional manner in the locality of thesnubbing pin, or it may be desirable to pass the yarn end 11 toapparatus between guides 86 and 74 for the application of a size or anantistatic agent.

In operation, an end of yarn from supply package10 is threaded throughguides 80, 82 and 84 to roll 18 and is then wrapped several turns(sufiicient to prevent the yarn from slipping to an appreciable extent)around the large diameter portion of rolls 18 and 54. As best seen inFigure 2 of the drawings, the yarn end 11 is then passed between blademember 62 and the portion 32 of roll 18 and thereafter to the smalldiameter portion of roll 54 so that it passes, while at an elevatedtemperature, about edge 64 in a sharply angular manner with the edge 64positioned at the apex of the angle. The position of blade member 62,relative to the periphery of portion 32 of roll 18, is preferably suchthat the yarn is caused to undergo a change of direction of at leastabout 90 in passing about the blade edge 64 and also such that the yarnhas little opportunity to cool prior to the time that it contacts edge64. In other words, if the edge 64 is positioned too great a distancefrom the periphery of portion 32 of roll 18, the yarn end 11 will coolto such an extent before passing about edge 64 that the highest degreeof elasticization is not obtained and, as a general rule, the edge ofthe blade 62 should not be removed from the periphery of portion 32 ofroll 18 a distance equal to more than about 20 times the diameter of theyarn to be processed. On the other hand, the edge 64 of blade 62 is tooclose to the periphery of portion 32 of roll 18, there may beinsufiicient room for the yarn to freely pass between the roll 18 andthe blade edge, and there is generally little advantage in attempting toplace the blade 62 such that its edge is a distance equal to less thanabout twice the diameter of the yarn from the periphery of portion 32 ofroll 18.

After passing about blade 62 to the small portion 58 of roll 54, theyarn end 11 is wrapped several turns around the smaller portions ofrolls 18 and 54 and is thereafter passed through guides 86 and 74 to thetakeup means 72. Passing the yarn from the large diameter portion ofroll 18 about blade 62 and to the small diame' ter portion of roll 54permits the yarn to shrink under the influence of heat immediately priorto the point that it contacts edge 64, and this not only relieves theyarn of stresses which would otherwise be present so that a higherdegree of elasticization is obtained, but also places the yarn under auniform tension as it is going about the blade edge.

It has been found that the tension in a moving end of continuousfilament yarn overfed between two points and allowed to shrink under theinfluence of heat will remain relatively constant even with relativelylarge variations in the degree of overfeed and with slight variations inthe temperature to which the yarn is heated. Therefore, the tension inthe yarn passing about th edge 64 of blade 62 remains relativelyconstant during normal operation. It has further been found that thetension developed in a thermoplastic yarn contracting under theinfluence of heat is a near optimum tension for edge elasticization sothat no supplemental tensioning or tension regulating devices arenormally required. 01"; course, if one is processing a yarn which hasbeen previously heat relaxed or which, for other reasons, is incapableof contracting under the influence of heat, then other means must beemployed for controlling the tension in the yarn as it passes about theblade edge 64, and an overfeed arrangement cannot be readily employed.

The most advantageous degree of overfeed depends pri marily upon thedegree of elasticization desired and upon the nature of the yarn beingprocessed. If one desires the highest possible degree of elasticization,the diameter of portion 58 of roll 54 with respect to the diameter ofportion 56 of roll 54 and the diameter of portion 34 of roll 18 relativeto the diameter of portion 32 of roll 18 should be such that the yarn inpassing from portion 32 of roll 18 to portion 56 of roll 54 is overfedsubstantially the maximum extent possible without the yarn becomingslack. While the maximum possible degree of overfeed will depend uponthe type of yarn being processed, as a general rule it will be found tobe from about 1% to 15% and, for example, with DuPont nylon type 200 isabout 141%. There may, of course, be instances where one do sires toobtain less than the maximum possible degree of elasticity and in suchinstances the degree of elasticity obtained can be lessened bydecreasing the amount of overfeed from the maximum possible. Forexample, with DuPont nylon type 200, a small measure of elasticity maybe imparted by overfeeding the yarn only about 1% and intermediatedegrees of elasticity may be imparted by increased overfeed until themaximum degree of elasticity is obtained with about overfeed.

With reference to Figures 6 and 7 which illustrate a modified form ofapparatus, the reference numeral 83 indicates a support member whichagain may be part of a draw twisting or spinning frame. Journaled abouta stub shaft 90 carried by frame member 38 is a roll member 92 having ayarn engaging peripheral surface 93 and having an end member 94 providedwith peripheral gear teeth 95. The roll 92 may be driven by any suitablemeans such as a spur gear 96 meshing with the teeth 95 and carried by adriven shaft 93 journaled through frame ber 83.

Positioned within roll 92 closely adjacent the inner surface thereof isa cylindrical heater element 161) which is designed to retain the yarnengaging peripheral surface 93- of roll 92 at an elevated temperature.The heater element 1% may suitably be of the electrical resistance typeand is supplied with electric power through conductors 1112 which enterthe roll 92 through an axial passageway in st 1) shaft 90.

The reference numeral 1124 indicates a second roll member journaledabout stub shaft 1% which is also carried by frame member 88. Rollmember 104 is provided with a yarn engaging peripheral surface 165 andis rotatable about an axis which is at an angle to the axis of rotationof roll 92, so that when an end of yarn 1113 from any suitable yarnsupply (not illustrated) is passed a pinrality of wraps around the rolls92 and 1&4, adjacent wraps of yarn remain separated from each other. Aswith rolls 18 and 54 in the apparatus illustrated in Figures l to 5 ofthe drawings, rolls 92 and 1114 together constitute a thread storagedevice of a conventional type.

The reference numeral 111 indicates a roll which has a yarn engagingperipheral surface 111 and which is jour naled for rotation on a stubshaft 112 also carried by frame member 38. Roll 111) is driven in anysuitable manner and is here illustrated as including an end member 1214which is provided with gear teeth which mesh with spur gear 96. A smallroll 116 engages the peripheral surface of roll 110 and is carried by apivot arm 11$ journaled on a small shaft 120 extending from frame member88. A spring member 122, mounted about shaft 120, normally biases roll116 into firm engagement with roll 110, and the two rolls functioningtogetherprovide a constant linear rate yarn advancing means. Rolls 116and 110 may be made of any suitable material, but at least one of therolls is preferably made of a resilient material, such as rubber, tolessen the slippage of an end of yarn passed between the nip formed bythe ,two rolls and to prevent cross-sectional deformation of the yarn.

The reference numeral 124 represents a blade member, having a yarnengaging edge 125, which is retained in position, with the edge 125 inclose proximity to theperipheral surface of roll 92, by means includingan ann 126 extending from frame member 88. Blade member 124 is analogousto blade member 62 in the embodiment of Figures. 1 to 5 of the drawingsand the statements earlier made with reference to the positioning ofblade 62 relative to portion 32 of roll 18, apply equally well to thepositioning of blade 124 with respect to the surface 93 of roll 92.

Guide means are provided to insure that the yarn'end 1% follows a properpath. A first yarn guide 128 carried by frame member 88 is provided forguiding the yarn about blade means 124 and to the surface 111 of roll110. A second guide means 129, also carried by frame member 88, isprovided to guide the yarn as itpasses between the rolls 116 and 116.

In operation, the yarn end 1198 is wrapped a suflicient number of turnsaround rolls 92 and 104 to prevent substantial slippage, and is thenwithdrawn from the surface of roll 92 and passed about the yarn engagingedge of blade 124. The yarn end is then passed through guide 128 to roll110 and thereafter between rolls 110 and 116. The yarn is then passedthrough guide 129 and eventually to a conventional yarn takeup device,not illustrated. The yarn upon the surface of roll 92 is heated to asuitable temperature for elasticization by heater element 100 and uponrotation of rolls 92 and 110, the end of yarn 108 is drawn about theedge 125 of blade member 124 in a sharply angular manner. In thisembodiment of the invention, tension regulation is preferably providedby driving roll 110 such that it has a lower peripheral speed than roll12 so that the yarn is allowed to contract under the influence of heatas it leaves roll 92 and passes about the edge of blade member 124. 7

With reference to Figures 8 and 9 of the drawings, which illustratestill another embodiment of the invention, the reference numeral 132represents a suitable support member which carries a stub shaft 134.Iournaled about stub shaft 134 is a roll member 136 having a yarnengaging tapered drum portion 137 and anend member 13? which is providedwith peripherally extending gear teeth.

The roll member 136 is driven in any suitable manner,

as for example, by a spur gear 139 mounted on a driven shaft 149 whichis journaled through frame member 132.

Mounted within roll 136 is a heater element 141 having a shapecorresponding to the inner surface .of the drum portion 137 of roll 136and which is for the purpose of retaining the drum portion 137 at anelevated temperature. The heater element 141 may suitably be of theelectrical resistance type and is supplied with power through electricalconductors 142.

Extending from frame member 132 at an angle to the axis of rotation ofroll 136 is a pin member 143 which is preferably made of an abrasionresistant material and which is provided with a smooth yarn engagingsurface. The roll 136 and pin member 143 constitute a yarn storagedevice of a conventional type, and when an end of yarn 144 from aconventional yarn supply, not illustrated, is passed a plurality ofturns about the roll 136 and pin member 143, adjacent turns of yarnremain separated from each other by virtue of the pin member being at anangle to the axis of rotation of roll 136.

The reference numeral 146 indicates a blade memher, having a yarnengaging edge 147, which is positioned adjacent the tapered peripheralsurface of the portion 137 of roll 136. The blade 146 is retained inposition by means including a support arm 148 which extends from framemember 132. The blade member 146 is analogous to blade member 62 in theembodiment of Figures 1 to of the drawings and should be similarlypositioned.

The reference numeral 150 generally indicates a constant tension takeupdevice here illustrated as comprising a takeup spool 152 positioned on afreely rotatable shaft 154 which extends between two slotted framemembers 156 and 158. Spool 152 is free to move up and down within limitsand is driven by peripheral contact with a traverse roll 160 of aconventional type which is carried by a shaft 162 also extending betweenframe members 156 and 158. The reference numeral 164 generally indicatesa constant torque transmitting device which is carried by a stub shaft166 extending from frame member 156 and which includes a first gear 168coupled to a second gear 170 through a friction clutch. The frictionclutch coupling may be conventional and is such that the torque urgingrotation of gear 170 remains substantially constant regardless of therelative speeds of rotation of gears 168 and 170. Means such as a nut172 threaded on shaft 166 is preferably provided for varying the amountof torque transmitted to gear 170 from gear 168. Gear 168 is positivelydriven for example by engagement with a spur gear 174 carried by adriven shaft 176 journaled through frame member 156 and traverse roll160 is driven through the constant torque device 164 by means of a gear178 carried by shaft 162 which meshes with gear 170.

Guide means are provided to insure that the yarn follows a proper yarnpath. A first guide means 180 is carried by frame member 132 and guidesthe yarn end 144 about blade member 146 in a proper manner. A secondguide 181 directs the yarn to still another guide means 182 which ispositioned centrally above the yarn takeup device 150 and guides theyarn to roller 160. Preferably, the guide 182 is removed from traverseroll 160 a distance which is large as compared to the length of thetraverse roll since this minimizes tension fluctuations.

In operation, an end of yarn 144 is passed a plurality of turns aboutroll 136 and pin member 143 and is then withdrawn from roll 136 andpassed about blade member 146 in a sharply angular manner. The yarn isthereafter passed about guides 180 and 182, around roll 160 and to thetakeup spool 152. The yarn is at an elevated temperature at the time itpasses about the edge of blade member 146 as a result of the surface ofroll 136 being heated by heater 141 so that, other conditions beingproper, a permanent tendency to coil is imparted to the yarn as it isdrawn about the blade edge. The tension.

in the yarn passing over the blade edge 147 is regulated by adjustmentof the torque coupling 164, but once established at a proper value,remains substantially constant regardless of the amount of yarn on spool152 as a result of the spool being surface driven.

It should be emphasized that a constant tension takeup means, such asindicated by the reference numeral 150 is generally advantageous onlywhen the taper of drum portion 137 of roll 136 is such and the positionof blade 146 with respect to portion 137 is such that any tendency forthe yarn to contract has been completely eliminated before the yarn iswithdrawn from portion 137 to be passed about blade edge 147. If theyarn has the ability to contract further at the time it is withdrawnfrom portion 137 of roll 136 to be passed about blade edge 147, it isgenerally advantageous to pass the yarn from the blade member to aconstant linear rate yarn advancing or takeup means, such as illustratedin Figures,6 and 7 of the drawings, so that the contraction of the yarncontrols the tension therein as it passes about the blade edge.Likewise, a tapered roll is suitable for use only with a yarn thatoriginally has the ability to contract under the influence of heat, andif one is proc essing a yarn which has been previously thermally relaxedor for other reasons will not contract on heating, a cylindrical rollsuch as indicated by the reference numeral 92 in Figures 6 and 7 of thedrawings should be employed in combination with a constant tensiontakeup means such as illustrated in Figure 8 of the drawmgs.

The apparatus of this invention is suitable for use with all yarns whichcan be edge elasticized with prior art equipment and when employing thenew apparatus, it will be found that conventional values for processvariables can be utilized. For example, the radius of curvature of theblade edge, the linear speed of the yarn about the blade edge, thetemperature of the yarn as it passes about the edge and the tension inthe yarn can all be conventional and, depending upon the type of yarnand other factors, the radius of curvature of the blade edge maysuitably be from .05 to 4 or more times the diameter of the yarn, theyarn temperature can range from room temperature to the stickingtemperature of the yarn, the linear speed of the yarn can be fromsubstantially zero to 1,000 or more yards per minute, and the tension inthe yarn can be from .05 to 2.5 gms. per denier. Of course, in someembodiments of the invention the yarn tension cannot readily be varied,but Where provision is made for varying the yarn tension, it may be setat any value conventionally employed with prior art edge elasticizingapparatus. Also, it is an advantage of the new apparatus that it permitshigher than usual yarn velocities, but conventional yarn speeds can beemployed if desired.

Having thus described our invention, what we desire to claim and secureby Letters Patent is:

1. Apparatus for processing a running length of yarn comprising incombination a driven roll, blade means providing a yarn engaging edge,means to position said blade means adjacent the periphery of said rollsuch that an end of yarn passing between the periphery of said roll andsaid edge can be withdrawn from the surface of said roll about said edgein an angular path with said edge positioned at the apex of the angle,and means to heat at least a portion of the yarn engaging surface ofsaid roll so that the yarn passes about said edge while at an elevatedtemperature.

2. In an apparatus for processing a running length of yarn and includinga yarn supply means and a yarn takeup means; a driven roll having a yarnengaging peripheral surface, means to heat at least a portion of saidsurface, blade means providing a yarn engaging edge adjacent saidportion of said peripheral surface so that an end of yarn passingbetween the periphery of said roll and said edge can be withdrawn fromthe surface of said roll and passed, While at an elevated temperature,about said edge in a sharply angular manner.

3. Yarn processing apparatus comprising in combination a yarn storagedevice for continuously storing and advancing a running length of yarn,means for retaining a portion of the yarn engaging surface of saidstorage device at an elevated temperature to thereby heat at least apart of the yarn carried by said yarn storage device, said yarn storagedevice being constructed to receive yarn at a greater linear rate thanthat which the yarn is discharged from said storage device so that theheated yarn is permitted to contract, blade means having a yarn engagingedge, and means for positioning said blade such that said edge is inclose proximity to the heated portion of said yarn engaging surface andsuch that the heated yarn can be passed about said edge in a sharplyangular path with said edge positioned at the apex of the angle.

4. Apparatus according to claim 3 wherein said yam storage devicecomprises a pair of spaced rolls at least one of which is driven.

5. Apparatus according to claim 3 wherein said yarn storage devicecomprises at least one stepped roll having first and second portions ofdilferent diameters and said heated portion of said yarn engagingsurface constitutes at least a part of the peripheral surface of theportion of said stepped roll having the larger diameter.

6. Yarn processing apparatus comprising in combination a yarn storagedevice for continuously storing and advancing a running length of yarn,said storage device including at least one roll with a yarn engagingperipheral surface, means for retaining at least a portion of theperipheral surface of said roll at an elevated temperature to therebyheat the yarn in contact therewith, blade means having a yarn engagingedge, and means for positioning said blade such that said edge iscontiguous to the heated surface of said roll so that the yarn can bewithdrawn from the surface of said roll and passed about said edge in asharply angular path While at an elevated temperature.

7. Apparatus according to claim 6 wherein said roll has a taperedportion of decreasing diameter and said edge is adjacent said taperedportion of the roll whereby the yarn is permitted to contract prior tothe point in the yarn path at which it is passed about said edge.

8. Apparatus according to claim 7 including means to withdraw the yarnfrom said blade edge and collect the same under substantially constanttension.

9. Apparatus according to claim 6 wherein said roll is of substantiallyuniform diameter and including means to positively withdraw the yarnfrom said blade edge and advance the same at a substantially constantlinear rate which is less than the peripheral speed of said roll wherebythe yarn is allowed to contract between said last named means and thepoint at which it leaves said roll.

10. Apparatus for processing a running length of yarn comprising a firstroll of substantially uniform diam eter, a second roll of substantiallyuniform diameter rotatable about an axis extending at an angle to theaxis of rotation of said first roll so that when an end of yarn ispassed a plurality of wraps about said rolls, adjacent wraps remainseparated from each other, means for driving at least one of said rolls,means for retaining at least one portion of the yarn engaging surface ofone of said rolls at an elevated temperature to thereby heat the yarn incontact therewith, a blade member having a yarn engaging edge, bladeholding means for positioning said blade member such that said edge iscontiguous to the heated portion of said yarn engaging surface so thatthe yarn can be withdrawn from said surface and passed, while at anelevated temperature, about said edge in a sharply angular path, andyarn advancing means to withdraw the yarn from said edge at asubstantially constant linear rate which is less than the peripheralspeed of said rolls, whereby the yarn is allowed to contract betweensaid yarn advancing means and the point in the yarn path at which itleaves said yarn engaging surface.

11. Apparatus according to claim 10 wherein said yarn advancing meanscomprises a pair of rolls at least one of which is driven.

12. Apparatus according to claim 11 wherein the rolls of said advancingmeans form a nip for the yarn and at least one of the rolls is formed ofa resilient material.

13. Apparatus according to claim 10 wherein the blade is so positionedthat the yarn engaging edge is spaced from said heated portion of saidyarn engaging surface a distance equal to from about 2 to times thediameter of the yarn to be processed and wherein said blade is sopositioned that the yarn in passing about said edge undergoes a changeof direction of at least about 90 degrees.

14. Apparatus for processing a running length of yarn comprising a firstroll, a second roll rotatable about an axis extending at an angle to theaxis of rotation of said first roll so that when an end of yarn ispassed a plurality of wraps about said rolls, adjacent wraps remainseparated from each other, means for driving at least one of said rolls,means for retaining at least one portion of the yarn engaging surface ofone of said rolls at an elevated temperature to thereby heat the yarn incontact therewith, said rolls having corresponding sections of differentdiameter such that the heated yarn is permitted to contract, a blademember having a yarn engaging edge, and blade holding means forpositioning said blade member such that said edge is contiguous to theheated portion of said yarn engaging surface so that the heated yarn canbe withdrawn from said heated portion about said edge in a sharplyangular path.

15. Apparatus for processing a running length of yarn comprising a pairof matched, stepped rolls having, in each instance, a first and secondportion, said first portion of each roll being of greater diameter thansaid second portion, and said rolls being rotatable about axes at anangle to each other so that when an end of yarn is passed a plurality ofwraps about said rolls, adjacent wraps remain separated from each other,means for driving at least one of said rolls, means for supplying an endof yarn to said rolls such that it enters a wrap around said firstportions of said rolls, means for withdrawing said end of yarn from awrap around said second portions of said rolls, means for heating atleast a part of the peripheral surface of the large diameter portion ofone of said rolls so that the yarn as it leaves the first portion ofsaid one roll to travel to the second portion of the other of saidrolls, is at an elevated temperature, blade means having a yarn engagingedge, and means for positioning said blade such that said edge is inclose proximity to the heated peripheral surface of said one roll andsuch that the yarn while at an elevated temperature can be passed aboutsaid edge in a sharply angular path in traveling from the first portionof said one roll to the second portion of the other of said rolls.

16. Apparatus according to claim 15 wherein said heating means isthermostatically controlled to retain the heated peripheral surface ofsaid first portion of said one roll at a substantially constanttemperature.

17. Apparatus according to claim 15 wherein said second portion of saidone roll is thermally insulated from said first portion of said one rollto thereby increase the temperature diiferential between the twoportions of said one roll.

18. Apparatus according to claim 15 wherein the blade is so positionedthat the yarn engaging edge is spaced from the heated peripheral surfaceof said one roll a distance equal to from about 2 to 20 times thediameter of the yarn to be processed, and wherein said blade is sopositioned that the yarn in passing about said edge undergoes a changeof direction of at least about degrees.

19. Apparatus for processing a running length of yarn comprising, incombination, a roll having a yarn engaging peripheral surface, means toheat at least an annular portion of said surface, blade means providinga yarn engaging edge, blade holding means to secure said blade meanswith said edge adjacent said annular portion of said roll surface, guidemeans to guide an end of yarn from said peripheral surface of said rollabout said blade edge in an angular path with said edge positioned atthe apex of the angle, and yarn advancing means to withdraw said yarnfrom said peripheral surface and about said blade edge.

20. Apparatus for processing a running length of yarn comprising, incombination, a driven roll having a yarn engaging peripheral surface,means to heat at least an annular portion of said peripheral surface,guide means to guide an end of yarn into contact with said peripheralsurface, a blade holding means for securing a blade member having a yarnengaging edge with said edge positioned adjacent said annular portion ofsaid peripheral surface, yarn advancing means for Withdrawing said yarnfrom said annular portion of said peripheral surface at a linear rateless than the surface speed of said driven roll to thereby result insaid yarn being thermally contracted a constant selected amount as itpasses from said peripheral surface to said yarn advancing means, andguide means, disposed in yarn flow relationship between said driven rolland said yarn advancing means, for guiding an end of yarn in an angularpath about the edge of a blade member secured by said holding means.

21. Apparatus for processing a running length of yarn comprising, incombination, a stepped yarn heater roll having first and second portionsof different diameters, means to heat at least a part of the peripheralsurface of said roll, blade holding means to secure a blade memberhaving a sharp edge such that said edge is proximate the peripheralsurface of the larger diameter portion of said roll, and means to guidean end of yarn into contact with the peripheral surface of the largerdiameter of said roll, about said edge in an acutely angular path withsaid edge positioned at the apex of the angle in said yarn path, andthereafter into contact with the peripheral surface of the portion ofsaid roll of smaller diameter.

22. Apparatus for edge-crimping a running length of thermoplastic yarncomprising, in combination, a driven roll having a smooth surfacedannular portion, means to heat at least said smooth surfaced annularportion of said roll, a blade member having a sharp edge, blade holdingmeans to secure said blade member in a fixed position such that saidedge is proximate said annular portion of said roll and such that saidblade member is spaced from said roll, so that a heated end of yarn incontact with said annular portion can be withdrawn therefrom and passed,while at an elevated temperature, in sliding frictional contact aboutsaid sharp edge in an angular path such that said edge is positioned atthe apex of the angle in said yarn path.

23. Apparatus for edge-crimping a running length of thermoplastic yarncomprising, in combination, a roll having a smooth surfaced annularportion, means to heat at least said annular portion of said roll, ablade member having a sharp edge, blade holding means to secure saidblade member in fixed spaced relationship to said roll with said sharpedge disposed proximate said annular portion, guide means for guiding amoving length of yarn into contact with said annular portion of saidroll and thereafter about said edge in an acutely angular path such thatsaid edge is disposed at the apex of the acute angle in said path andsuch that said yarn is in sliding frictional contact with said edge, andmeans to drive said roll such that said heated annular portion has asurface speed approximately equal to the linear rate of movement of theyarn in contact therewith.

24. Apparatus according to claim 23 wherein said roll is a stepped rollhaving portions of larger and smaller diameter, wherein said heatedannular portion comprises the larger diameter portion of said steppedroll, and including guide means to guide said yarn into contact with thesmaller diameter portion of said roll following its passage about saidsharp edge.

References Cited in the file of this patent UNITED STATES PATENTS1,988,313 Greene Ian. 15, 1935 2,156,244 Mahoney Apr. 25, 1939 2,244,415Arnold June 3, 1941 2,318,998 Ingalls May 11, 1943 2,339,323 Field Ian.18, 1944 2,464,502 Hall et al. Mar. 15, 1949 2,639,485 Ambler May 26,1953 2,673,546 Newton Mar. 30, 1954 FOREIGN PATENTS 581,5 6 GreatBritain Oct. 16, 1946 585,368 Great Britain Feb. 5, 1947

